With rapid growth of electronic terminal equipment in recent years, the electronic equipment is downsized, made thinner and becomes high performance. A semiconductor device mounted therein is downsized and densified in association with this, and flip-chip mounting is rapidly spread as a method of mounting a semiconductor chip on a circuit board.
In order to enhance reliability of the semiconductor device, an underfill material is filled in a gap between the chip and the board. As a method of filling the underfill material, a method of filling the underfill material in a gap between the chip and the board by use of a capillary phenomenon is common; however, there are problems that an unfilled state easily occurs and production cost is high. As a technique for solving these problems, a technique of forming an underfill material on a wafer and bonding an individualized chip to aboard is contrived. A method of forming an underfill, material on a wafer includes a method of forming a resin composition applied in the form of a film on a wafer through vacuum thermally laminating treatment or the like, and a method of directly applying a resin coating material to be formed on a wafer.
As described above, storage stability at room temperature and properties curing in a short time are required of the coating agent for forming a resin layer on a wafer, and high strength is required of a cured product. It is common to use an epoxy composition as these materials; however, the epoxy composition has a problem that strength is low although it is characterized by having excellent adhesiveness. Therefore, as a method of improving this problem, a resin composition having a polyimide mixed therein is reported. (for example, Patent Document 1, Patent Document 2).